Cylinder ridge grinder



March 1951 D. w. BALDWIN ET AL 2,546,490

CYLINDER RIDGE GRINDER Filed Sept. 20, 1947 4 Sheets-Sheet 1 Man/4M H. Cunt/v76, Zhwentors.

(Ittorneg March 27, 1951 13. w. BALDWIN ET AL CYLINDER RIDGE GRINDER 4 Sheets-Sheet 3 Filed Sept. 20, 1947 MAL/0M fl CLEME/VTS,

DOA/52o W 577401444, 113/71. FRED G flranpsam md Ma 3nvcutors.

Gttorneg March 27, 1951 D. w. BALDWIN ET AL CYLINDER RIDGE GRINDER Filed Sept. 20, 1947 4 Sheets-Sheet 4 4 M W amp 0 m RM =a 1 Ni F120 3 121 Mum/v17. CZEHE/VTJ,

- 3lmentors.

@filillllllllllllllllllllllllll (Ittomeg Patented Mar. 27, 1951 UNITED STATES PATENT OFFICE CYLINDER RIDGE GRINDER Donald W. Baldwin, Los Angeles, Wilfred G. Thompson, Pasadena, and William A. Clements, Glendale, Calif.; said Thompson and said Clements assignors to said Baldwin Application September 20, 1947, Serial No. 775,228

7 Claims. 1

This invention relates generally to rotary grinders, and more particularly to grinders of this class which are used for shaping the interior walls of cylinders in engines, pumps and like devices.

When disassembling an internal combustion engine, for example, for the purpose of replacing worn parts or reboring the cylinders, it is frequently necessary, or at least expedient, to remove the pistons through the top of the cylinders. In engines where considerable wear has taken place, such removal is often diflicult because of an inwardly projecting annular ridge near the upper end of each bore.

A cylinder ridge of any appreciable size prevents the removal of the piston through the top of the cylinder due to the fact that the piston rings, normally in pressure contact with the cylinder walls, catch under the ridge and lock the piston in the cylinder. Therefore it is desirable when disassembling an internal combustion engine, to first remove the cylinder ridges by cutting or grinding before attempting to remove the pistons.

As is well known in the art, the wear in engine cylinders of the class described tends to elongate the transverse cross section of the cylinder and produce an oval shaped bore. Thus the cylinder ridge, being circular in its cross section, has a considerably greater inward protrusion at the lateral edges of the cylinder bore than it does at the forward and rear edges thereof.

One method of cutting away the cylinder ridge of an elongated cylinder would be to enlarge the diameter of the bore at the upper end until this diameter was equal to or greater than the major diameter of the worn portion of the cylinder. This is an unsatisfactory procedure, however, since an inordinate amount of material must be removed in order to permit removal of the piston, and furthermore, a shoulder is left at the forward and rear edges of the piston, since the diameter of the cut-away portion of the bore would then be greater than the longitudinal diameter of the worn portion of the cylinder.

It is, therefore, desirable in the removal of cylinder ridges to remove only enough material from the wall of the cylinder to bring the walls into continuous alignment, whatever their crosssectional shape may be. In order to do this, it is necessary to guide the cutting or grinding tool used in the removal of the ridge, by a guiding member in contact with the worn portion of the cylinder walls. One procedure previously followed is to employ a rotating cutter with a stationary guide in alignment with the cutting pcriphery, and to then move the cutter around the interior wall of the cylinder in planetary fashion with the cutter in contact with the ridge to be removed and the guide member adapted to contact the worn wall so as to prevent further cutting when the ridge has been removed.

When a single cutter is used in the manner just described, there is a pronounced tendency for the cutter to chatter or bounce away from the walls as it moves around its orbit. Furthermore, it has been the usual practice to deliver the mechanical power necessary to rotate the cutting elements manually; usually by means of a ratchet wrench affixed to the means provided for suspension and location of the rotating cutter within the cylinder.

It has been proposed to overcome the foregoing difficulties by performing the ridge removal operation with two or more planetary grinders or cutters driven from a common central power source. Such arrangements are also adapted to be rotated in planetary fashion to carry the rotating grinders or cutters in an orbit around the inside of the cylinder wall. In order to remove only the ridge portion, however, it is necessary that the orbital paths followed by the various cutters be adjustable in diameter so that they may, if necessary, move in and out as they progress around the cylinder walls to accommodate for the aforementioned oval shape thereof. Furthermore, it is necessary that the path of grinders of the class just described be adaptable to fit a wide variety of cylinder sizes if they are to be of any practical value to automotive repair shops, and the like.

Bearing in mind the above listed desiderata and the disadvantages of previous devices, it is a major object of the present invention to provide a grinder of the class described which employs a plurality of planetary cutters operating from a common power source and adapted to be adjusted for operation on cylinders of various sizes.

It is another object of the invention to provide a cutter of the class described in which each cutter is constrained to operate within an orbit corresponding to the cross-sectional shape of the worn portion of the cylinder.

t is still another object of the invention to provide a power transmission in a tool of the class described in which the mechanical power for rotating the cutting elements and for carrying them around the desired orbit is provided from a common central source and which still permits cutting elements to be adjusted as above described, and which does not employ universal or flexible shafts.

A further object of the invention is the provision of a novel spring-loaded mechanism used to guide the grinding elements in their proper orbit and to efiect pressure contact thereof with the cylinder wall. 1 p

The foregoing and other objects and advan-- tages will become apparent from the following description of a planetary cylinder ridge grinder which embodies the invention. Y, Y

Briefly described, the apparatus embodying the invention comprises-a cylindrical head; a number of rotary grinding stones 'journally held in the head and projecting below the lower surface; in some embodiments an idler roller, also projecting below the lower surface ofcthe head arranged to roll against the inner walls 01 the cylinder and spring-loaded to hold the grinding stones in operative contact with the cylinder ridge; a'planeta'ry gear transmission to deliver power from a common central shaft to the rotary stones; means to simultaneously adjust the 'stone'sjin a generally radial direction on the head adapted to support the grinding'apparatus in operativepositionover acylinder. The rotary stones and the idler roller are arranged so that their rotary axes fall on a circle whichis concentric about the axis'of rotation of the head. Since the head itself rotates about the axis of the centralshaft, this shaft is held substantially at the axis of the cylinder bore at'all times, thus obviating the necessity of universal or flexible 'shafting to deliver power to the stones.

'in Figure 1;

Figure 3 is a partial plan view looking upwardly along the line 3-3 in Figure 1;

Figure 4 is an enlarged, partially sectioned elevation'taken on a vertical plane through the central axis of the apparatus illustrated in Figure 1;

Figure 5 is a sectional plan view looking upwardly on the line 55 in Figure 4; v

Figure 6 is an elevational partially sectioned view taken on a vertical axial plane through the idler roller used in the apparatus illustrated in Figure 1;

Figure 7 is a partially sectioned plan view taken on the line 7- 1 in Figure 6;

Figure 8 is a diagrammatic perspective view of the transmission systems employed in the apparatus illustrated in Figure 1;

Figure 9 is an elevational section taken on'an axial plane through a modified idler roller of the apparatus illustrated in Figure 1, showing the same positioned against'a cylinder ridge;

Figure 10 is a diagrammatic plan view showing the relative positions occupied by the rotary stones and idler roller during progressive operation of the apparatus illustrated in Figure 1;

Figure 11 is a partially sectioned elevational view of a second modified form of idler roller;

Figure 12 is a fragmentary vi'ew of a portion of the apparatus illustrated inFigure 11 with the parts shown in an operative position;

Figure 13 is a sectional view taken on the line l3l3 in Figure 4 but showing a modified form of the orbit adjusting means which incorporates spring loading means;

Figure '14 is a fragmentary elevational section taken 'onthe line 14-! l in Figure 13; and,

Figure 15 is a fragmentary view of the parts shown in Figure 13 but with said parts in an operative position.

In Figure 1 of the drawings, the ridge grinder embodying the invention is illustrated supported inoperative position on an: engine blook28. The grinder is comprised of a rotating he'adi5 which supports "a number "of rotary grinding stories 15 dependent therefrom, and in some embodiments an idler roller [2 (not visible inFi gure 1). As can be seen in Figure '1, these stones [6 project downwardly into a cylinder '26, and are positioned to operate f on a cylinder ridge 25, the removal of which will permit removal of the piston 2''! from thecylinder '25. The head l5 issup'ported in thep'ositio'n shown by means of a non-rotating shank I! held in'a collar 230i a tripod frame 26. As can be seen in Figure 2, the three legs of the tripod'res't on the upper surface of the cylinderblock 2'3,'one'of'the legs 2| being hingedly'supported by a vertical hinge pin 22 at its upper endywhereby theleg may be swung one way or the other to'avoid such studs as maybe left in the surface'ofthe cylinder block 28. As is also shown in Figure 2, one of the legs of the tripOdZil is placed inabutment with the collar 29 whereby to prevent rotation "of the shank i'l therein. Under conditions of operation of the tool where no studs are left in the cylinder block, rotationof thesupporting tripod may be'pr'evented by hand by the operator.

The weightof the head 'l5and the members depending therefrom, is supported by acompression spring l3 which'surrounds the upper portion of the shank H in 'abutment 'with the collar'23 and an upper collar [9 formed on the shank'll.

Power to rotate both thehead l 5 and the stones I6 in a clockwise direction as viewed in Figure 2, is delivered'th'r'o'ugha drive shaft 39 coaxially positioned and journaledin'the shank'll.

Thus it will be seen that asthe grinder operates on the ridge 25, the entire head I 5 and the stones l6 carried therebymay bemanually oscillated up 'and downto bringfdiiferent peripheral portions of pressure is'neces'sary to 'efiect the aforesaid oscillatorymotion.

Turning now to adescriptionof the power transmission and adjustment means contained Within the head 15, referenceismadeito Figures 4 and 8. v Firstl considering the r'rleans for delivering the rotarypower to each of theistonje' s l6, it should be noted that suchpoweris derived 45 to the intermediate plate 41.

from the main power shaft 30 which rotates in a clockwise direction (looking up), and is transmittedthrough an internal gear 3| keyed to the lower 'end of the shaft 39 and through pinions 32 to idler shafts 33. Thence the power is delivered through idler gears 34 keyed to the lower end of the idler shafts 33 to pinion portions 36 cut in theupper ends of vertical shafts 35, which shafts project below the lower surface of the head l5 and upon each of which, one of the cylindrical stones 1 6 is mounted.

' A lower journal bearing 33 and an upper journal bearing 39 support the shaft 35 for rotation in an adjustment cylinder 54 to be described presently. Downward thrust on the shaft 35 is taken by 'a collar 3! affixed thereto in a position to frictionally engage a flange on the upper end of the journal bearing 38. It is only necessary to deliver power to the stones [6, since the idler l2,

if used, will rotate by reason of its frictional engagement with the wall of the cylinder. Thus the power transmission elements are provided in only those of the rotatably cylindrical supports 54, which carry stones I6.

It will be noted that the relative gear diameters are such as to effect a rotary speed of the stones [6 considerably greater than that of the shaft 30. Following the arrangement of the power transmission gears, it will also be noted that clockwise rotation of the shaft 30 results in clockwise rotation of the idler shaft 33, which 'in turn results in anti-clockwise rotation of the stone support shaft 35.

Considering next the construction and operation of the head 15 itself, it will be remembered that this portion is adapted to rotate in an anticlockwise direction whereby to carry the stones [6" around an" orbit inside the cylinder upon which they are. operating. Such motion of the head I5 is made possible by the provision of a flange 4| formed on the lower end of the shank l! to which a sub-flange 42 is secured by means of attachment screw 4|. The flange 4i and the sub-flange 42 secure a'relatively large-diameter flanged'bearing 43 therebetween, upon'which is supported a ring shaped upper plate 44 for the head l5, which is adapted to rotate on the bearing 43 around the axis of the shank l1. The balance of the head I5 depends from the upper plate 44 and comprises a ring gear section 45, a ring shaped spacer 46, an intermediate plate 41, a lower section 48 and a bottom plate 49.

All of the ring shaped portions 44 through 49 are. of the same outer diameter whereby'to provide a head of generally cylindrical shape. The various portions just described are secured together by threescrews 59 which secure the bottom plate 49 and the lower section 48 to the intermediate plate 41, and by a number of peripheral screws 52 which secure the upper plate 44, the ring gear 45, and the ring shaped spacer As will be noted in Figure 4, various portions of the ring shaped members of the head l5 are cut away internally to provide spaces for the transmission members just described, and other members about to be described. v

As has been previously stated, it is desirable to adjust the diameter orbit traveled by the stones [6 and the idler l2. This adjustment is effected by mounting the shafts 35, of the stones l6 and p a shaft 35a of the idler l2 in rotatable cylindrical support blocks 54. These support blocks are mounted for limited rotary motion within the head I5 and areeach comprised of a lower section 6 55, an intermediate section 56, an upper section 57, and an adjustment gear 58 of the upper section 51. The various parts of the support cylinders 54 are secured together by screws 59 which secure the upper and intermediate sections 51 and 56 respectively to the lower section 55 and by screws 60, which secure the adjustment gear 58 to the upper section 51.

As will be seen from an examination of Figure 3, arcuate slots 65 are formed in the lower plate 49 of the head I5 through which the shafts 35v and 35a project. Thus rotation of the cylindrical support member 54 within the lower section 43 serves to swing the shafts 35 and 35a inwardly or outwardly along the arcuate slot 65 whereby to change the diameter of the aforesaid orbit. It will also be noted from an examination of Figures 4 and 5 that such orbit adjusting rotation of the support member 54 is about an axis coincident with the axis of the idler shaft 33. Thus the adjusting rotation of the cylinder 54 does not disturb the meshing relationship between the ring gear 3| and the idler pinion 32.

Simultaneous rotation of the three support cylinders 54 is effected by means of an internal ring gear 5| which is mutually meshed with the three adjustment gears 58. As can be best seen in Figure 4, the outer periphery of the ring gear 5! projects somewhat beyond the cylindrical surface of the head I5 and is knurled, whereby this ring may be grasped and rotated to simultaneously rotate the three supporting cylinders 5 Thus since the shafts 35 and 350. are simultaneously adjusted, they are always positioned in circle concentric with the axis of the shank l? and the rotating head [5. When stones l5 and the idler l2 have been adjusted to the desired circle diameter, the ring gear 5! is clamped in that position by means of a set screw 52 threaded into the spacer 46 in the intermediate plate 47 in a position to engage the upper surface of the ring gear BI.

Turning now to a discussion of the means whereby the head [5 is driven in anti-clockwise rotation (looking up) as previously described, it will be noted in Figure 8 that a pinion 55 is secured to the power shaft 30 near the lower end thereof and is positioned to engage a pair of step gears 66. Each step gear 66 has a stub shaft 69 keyed therein and projecting upwardly to 1'0- tatably support the step gear in a journal bearing 15 pressed into the sub-flange 42. As best seen in Figure 8, the pinion S5 meshes with the large diameter portion 51 of the step gear 65 'while the small diameter portion meshes with the ring gear section 45, which as previously de scribed, is a fixed portion of the head 45. Thus, clockwise rotation of the shaft 39 effects anticlockwise rotation of the step gears 56, which in turn effects anti-clockwise rotation of the ring gear section 45, and hence the head 35, pre viously described.

The structure just described is adapted to support and rotate cutters and stones of various types on the lower end of the shaft 35. The grinding stone 15 illustrated herein is of a conventional type comprising a cylindrical stone portion 12' cemented or otherwise secured to a metal core 13, which in turn is adapted to be secured by means of a set screw 14 to the lower end of the shaft 35. Secured to the lower end of the core 13 by means of screws "56 is a guide roller section 15 constructed of a material which is adapted to be dressed off to a diameter equal 'to that of the stone portion 12 during the operation ""of -'-aressirig the stone afnd whichwill fwear err in use at a rate approinhiatelyjth'a't "of partitular stenet ed. "It will be noted from "an examination of Figural that the guide-"sectioirifi is positioified adjacent the worn part of the "cylinder '25. Thus when the guide "section 1"?5 comes in contact "with the cylinder w'alLthe grinding operation of the stoneportion I2 ceases, since the ridge "25 has, by that time, been re- In=- order that the stone portion 12 continue l to operate witlroptimum e fiicie'ncy while'iti's'being rotated and revolved about'its orbitfit is necessar that considerable outward pressure "be continuo'usly appliedduring this-operation. 'lihe'effect of such pressureis illustratedinFigure lO'wh'ere "in it will be seen that as "the grinding proc'ee'ds toward a limit indicated by 'the dotted 1'irie's"there in, thelidleriZ, if forced outwardly ona'ra'dial line, will maintain a constant peripheral pres- "sure on the stones "I6. The phantom lines in Figure "sliow the ultimate position'assumed by the stones I6 andthe-idler I2 at the termination of the grinding operation.

Various means may be used to efiect the outward pressure of the idler roller I2, one of which is illustrated in Figure 6. Referring to Figure 6, it Will be noted that the rotating portion of the idler I2 is comprised of an outer shell Be and an upper collar 8| secured thereto by means of screws 82. The shell 89 rotates on bearing r011- ers 83, which-in turn are supported on an inner core portion 85 and held against vertical displacement by plates 86 and 86' secured to'the lower and upper surfaces of the core 85 by screws 8?. 7

-As best seen in Figure '7, a bore 88 of rectangular cross section-is formed in the core 85. The shaft 35a, which supportsthe idler i2, is formed with a rectangular portion-89 on its lower end adapted to have a sliding fit against two sides of the bore 88. Thus the core 85'is adapted'to move laterally as viewed in Figure '7 with respect to the shaft portion 89. Three transverse pins 98 are pressed-into the core '85 and have a sliding fit in the shaft portion 89 whereby to maintain a parallel relationship between the shaft portion 39 and the core at all times. Three compression springs 9i, surrounding the pins 98 and positioned between the right-hand edge of the rectangular shaft portion 89 and 'the'righthand inner surface of the rectangularbore'fifi, serve to urge the core 85 to the right in Figure 6.

It is essential that the alignment ofthe rectangular shaft portion'BS be such that 'at'all times th outward motion urged by the Springs 9! is radial with respect to the axis of the head I5. In order to maintain such alignment, a pair of flats 92 are formed on the shaft 35a, which are engaged b a slotted arm 5 which is pivotally secured by a shoulder screw 85 at the center of the bottom plate 98. Thus as the shaft'35a is moved in'the arcuate slot 65 by rotation of the support cylinder 55, the alignment of the flats on the shaft with the slots in the arm 9:3 maintain the properly aligned position of the rectangular shaft portion'BB at all times, regardless of the adjusted position of the idler roller I2, the shaft 35a being free to turn somewhat in the cylinder 54.

Qnealternate form of idler roller is illustrated in Figure Qwherein it'will be seen that acentral core I00 is'provided and'sec'ured to'theshaft by means of 'a }set"screw -14 An intermediate "core II "is rotatably sup orted by hearing rollers "83 titaat lls 8 manner-core Ito-anti i "rotatably sappertea 5y bearing rollers 8 3 '-on "the inner core T00 by "i rieaiis-iiffa plate-86 and screws 81. 'Anbuter steel shell 102 is secured to {the iritei'medfate'hore IiH by-means of a deformablebushing IIl3 ffconenacted of rubber ona'simila'r material. the intermediat 'co're I I3 I the deformable bushing l Il3,'and-'the outer she'll l-ez rotate-as aiunit. will-be notedin Figure "9, whe'nthe shell "1 52 is brought into pressure contact with a rid'geZB in the cylinder 26, the deformable bushing I03is 'bompres'se'd on the contact "side'andstretched' on the opposite side whereby to'*mairita'in the con. tact pressure against the ridge asiiidicated in FigurelO. As it best-seen in'Figu'res8and"9,the 'lower'ends of the stones l'fici the'idlerroller -li fh-a ve a'conica'l'portion I04 and'are thus adaptefd to be forced into a' cylinder wherebyto compress the deformable bushing as -shown in "Figure "9, "'or'if the roller oPFigureB isempl'oye'd, tocompress th s'pringse' I. I

Asecondalternate'form of idler roller isillus- *trated in Figuresll andi'2. From anexamin'ation of Figure 11, itwill'benotedthat the idler "shaft isjin this'modified-form,separatedf'int'o an upper portion llll'a'nd'a'lower portion H2. "The upper portion H0 "and the-lower portion I I2 are "connected-by a relativel heavycoil spring III. aheucargroove is formed in each'o'fthenha'ft portions III) and H2, and the spring "III is threaded onto this helical groove'in screw'fashion.

The ends of the spring are bent inwardly "as indicated at I I8 to enter h'oles'l I'9'form'ed inithe shaft portions I IEl'and' I I2.

I In the operation of the secondmodified form "illustrated in Figure "11,'b'oth of the shaft porftions I I0 and II Z'are n'on roating with respect to j'the head I5. The rollerl I4 of" the second'mo'di- "fied form rotates on a rollefbearing H5 'and'is secured to the shaft 'by "means of "a "cap I'I'B secured to the lower end of the shaftwith ascrew 'I I1. Upward thrustof th roll'er lidis taken "by a collar portion I I3 formed on "thesh'aift'"H2.

Whenthesecondmodified roller is placed in operation in the mannerdescribedin connection "tliur'the previous embodiments, the lower Jshaft portion H2 is, by reasoniof the'pressure'eng'age- 'ment of the roller H i against'the cylinder wall, deflected with respect to the upper shaft [portion I'I'Il'as illustrated in Figure 12. Such deflection is toward the'aXis' of'the head I5 "and isjof course' resiliently resisted by the spring II. Thus the desiredniverg'er'it pressure is 'efiected in the same mannerasdescribed in connection with the previousembodim'ents.

'In' certain instances "itma 'be desirable to' dis- "pense'vvith the'idler ro11er"'entirely and emplo lthre'e ro ary stones'lt or cutt'ers, instead of the two described in theprevious embodiments. In order to'obtain resilient divergent motion of the three rotary stones employed inth-is "inanner a "modificationbf the orbit adjusting ring gear has 'beenprovided. Insteadof :thesin'gle "ring gear"? I previousl ein'ployedior this "purpos 'the 'ring gear modified formisseparat'ed into two concentric 'rin sh'aped" ortions and 2112 I. "The innermost portion .12! -is.provided with internal "gear" teeth corresponding toiithose on the single -ring gear"6I' or the .pi'eyicus embodiment. The outer portion 120 "is held in fslidable concentric relation with the 'ihner-portionZfl, the twof-p'ortion 'Ibeingheld in place-betweenfthe' lower'head section-I 5 andthe intermediate-transversefplate 41.

' When 'tl'ire''r ota'fystiinsIt areriiployed. such stones are rotatably mounted in three identical adjustment cylinders 54, and power is transmitted to the stones through three identical transmission systems comprising the idler pinion 32, the idler shaft 33, the idler gear 34, and the pinion portion 36 on the shaft 35.

In order to resiliently urge divergent motion of the three rotary stones of the last mentioned modified form, a pair of compression springs I22 are provided and mounted in cavities formed in the inner and outer portions of the ring gear [H and I20 respectively. Thus when the outer portion I20 is rotated, it drives the inner portion I2I through the compression springs I22. If such motion of the inner gear portion I2I is resisted, as for example by the stones coming in contact with the cylinder wall, further motion of the outer gear portion I20 results in compressing the springs as indicated in Figure 15. Conversely, if

the three stones are forced inwardly, as for eX- ample by forcing them into a cylinder having a diameter less than the orbit to which they have been adjusted, such motion of the stones will be communicated by the gears 58 to the ring gear portion I 2I, whereby to compress the springs as shown in Figure 15.

Thus it will be seen that by clamping the outer ring portion I20 in an adjusted position with the stones lying on an orbit slightly larger than the cylinder into which they are to be placed, the stones will, when inserted into the cylinder, maintain their outward operative pressure. In order to so clamp the modified ring gear, the clamping screw 62 is positioned to engage the outer portion I20.

The operation of the device in the cylinders of automotive engines is as follows. The cylinder head of the engine is removed, preferably leaving one Or more head retaining studs in place in the block adjacent each of the cylinders. The stones I6 and the idler roller (if employed) are then adjusted by loosening the set screw 62 and rotating the ring gear 6! until the outer peripheries of the stones I6 fall on a circle slightly larger than the largest diameter of the cylinder to be operated on, whereupon the screw 62 is retightened. The apparatus is then lowered into the position as indicated in Figure 1, power is applied from a convenient source (not shown) to the shaft 30. As the head I5 and the stones I6 carried thereby rotate, alternate pressure is applied to the collar I9 whereby to vertically oscillate the stones as they operate on the ridge 25. As the grinding operation proceeds, and the ridge 25 is removed, the lower guide section portion of the stones I6 will come in contact with the worn surfaces of the cylinder wall whereby to prevent further grinding operation.

In cases where extreme wear of the cylinder walls has taken place, it may be necessary to stop the operation at some point and readjust the stones I8 outwardly to renew the grinding pressure. In most cases, however, the single initial adjustment is sufficient to provide adequate displacement of the stones as the work progresses.

As in most grinding equipment of the class described, it is necesary to periodically dress the grinding stone. Such operations are usually performed with a diamond dressing tool in the manner well known in the art. When the stones are so dressed, however, care must be taken to also dress the guide portion I5 to an equal diameter.

While the grinding apparatus shown and described herein is fully capable of achieving the objects and providing the advantages hereinbefore stated, it is capable of considerable modification within the spirit of the invention. Therefore I do not mean to be limited to the forms shown and described herein, but rather to the scope of the appended claims.

We claim:

1. In cylinder shaping apparatus of the class described: a head mounted and adapted for powered rotation; a plurality of power driven rotary tools j ournaled in said head and projecting therefrom whereby to engage the interior wall of a cylinder; and idler means including a shaft mounted in said head and projecting therefrom, a nonrotating core mounted for lateral translatory motion on the outer end of said shaft, a roller journally mounted for free rotation with respect to said core and positioned to engage said cylinder wall, and yieldable resilient means connected between said core andv shaft and stressed to urge outward motion of said core whereby to effect operative pressure.v engagement of said tools against said cylinder wall.

2. In cylinder shaping apparatus of the class described: a rotatable head; a plurality of cylindrical members journaled for limited rotation in said head about axes equally spaced from a central axis of said head, said members having relatively immovable gear portions thereon; an internal ring gear rotatably supported in said head and meshed with saidgear portions whereby to effect simultaneous rotation of'said members; a plurality of rotary tool shafts, each journaled in one of said members on an axis spaced from the rotary axis of said member whereby rotation of said members moves-said tool shafts with respect to said central axis while maintaining the same on a circle about said central axis at all times; a member supported in said head for'manual movement to lock said ring gear with respect to said head whereby to hold said tool shafts at any adjusted position thereof; a plurality of idler shafts each concentrically journaled in one of said members; a pinion on each of said idler shafts; a pinion on each of said tool shafts; a gear on each of said idler shafts, said idler gear being meshed with the pinion on the tool shaft mounted in the same member with said last mentioned idler shaft; a journally mounted drive shaft concentrically positioned on said central axis and projecting into said head; a gear adjacent the inner end of said drive shaft having common meshing engagement with said idler pinions whereby to simultaneously drive said idler shafts and tool shafts.

3. In cylinder shaping apparatus of the class described: a tool head; a plurality of cylindrical members journaled for limited rotation in said head about axes equally spaced from a central axis of said head, said members having relatively immovable gear portions thereon; an internal ring gear rotatably supported in said head and meshed with said gear portions whereby to effect simultaneous rotation of said members; a plurality of rotary tool shafts, each journaled in one of said members on an axis spaced from the rotary axis of said member whereby rotation of said members displace said tool shafts with respect to said central axis while maintaining the same on a circle concentric with said central axis at all times; means including a member mounted in said head for movement to interlock said ring gear and head whereby to hold said tool shafts at any adjusted position thereof; a plurality of idler shafts each concentrically journaled in one 1 1 of said cylindrical members; a. pinion on each of'said" idler shafts; a pinion on each of said tool shafts; a gear oneach of said. idler shafts, said idler gear being meshed with the pinion on the tool shaft mounted in the same member with said last mentioned idler shaft; a coaxial bearing formed in said head; a non-rotating. shank projecting within said bearing and adapted to rotatably support said head; a drive shaft coaxially journaled in said shank and projecting into said head; a first gear fixed to said drive shaft adjacent the inner end thereof and. having common meshing engagement with said idler pinions whereby to simultaneously drive said idlers and tool shafts; a second drive gear fixed to. said drive shaft adjacent the inner end thereof; a plus rality of gears journaled in said shank and meshed with said secondldrive gear; a driven gear integrally formed in said head' and meshed with said gears in said shank whereby to drive said head from said drive shaft; and a support having a plurality of legs and a central collar" portion slidingly engaged with said shank to support the same with said head adjacent the open end of a cylinder and with said tool shafts project.- ing thereinto, said collar portion being adapted to permit reciprocating axial motion of the shank. 4. In cylinder shaping apparatus of the class described: a tool head, a plurality of cylindrical members journaled for limited rotation in said head about axes equally spaced from a central axis of said head, said members having relatively immovable gear portions thereon; an. internal ring gear rotatably supported in said head and meshed with said gear portions whereby to effect simultaneous rotation of said members; a plurality of rotary tool shafts, each journalecl in one of said members on an axis spaced from the rotary axis of said member whereby rotation of said members displaces said tool shafts with respect to said central axis while maintaining the same on a circle concentric with said central axis at all times; an interlocking member supported for movement against said gear to clamp said ring gear against movement whereby to hold said tool shafts at any adjusted position thereof; a fixed shaft in one of said members and projecting therefrom in parallel spaced relationship with said tool shafts, said fixed shaft being so positioned on said member as to be on said concentri'c circle with said tool shafts at all times; an idler roller on the outer end of said. fixed shaft,

said roller including resilient means to urgev out- Ward motion thereof; a plurality of idler shafts each concentrically journaled in one of said members; a pinion on each of said idler shafts; a pinion on each of said tool shafts; a gear on each of said idler shafts, said idler gear being meshed with the pinion on the tool shaft mounted in the same member with said last mentioned idler shaft; a coaxial bearing. formed in said head; a non-rotating shank projecting within said bearing and adapted to rotatably support said head; a drive shaft coaxially journaled in said shank and projecting into said head; a first gear fixed to said drive shaft adjacent the inner end thereof and having common meshing engagement with said idler pinions whereby to simultaneously drive said idlers and tool shafts; a second drive gear fixed to said drive shaft adjacent the inner end thereof; a plurality of gears journaled in said shank and meshed with said second drive gear; a driven gear integrally formed in said head and meshed with said gears in said shank whereby to drive said head from said drive shaft; and a sup- 12 port, having, a plurality of legsv andacentral col.- lar portion surrounding said shank to. support the same withsaid head adjacent-the openend ofa cylinder and with said tool shafts projecting thereinto, said collar portion being, adapted to permit reciprocating axial motion of the shank,

5. In cylinder shaping apparatus of the class described: a head mounted and adapted for powered rotation; a plurality of cylindrical members in said head each adapted for limitedirotae tion on an axis parallel to, but. spaced from the rotary axis of said head; gear means including asingle gear rotatably secured in said head and in common meshing engagement withsaid. cylinder. members whereby to effect simultaneousrotation thereof; a rotating member resiliently connected by a yieldingly deformable member to said gear means whereby to rotate the. same while permitting resiliently resisted relative mo.- tion between said gear means and rotating member; means in said head to clamp said member. in an adjusted position thereof; and a plurality ofpower driven rotary tools each projecting. be, yond said head whereby to engage the interior wall of a cylinder and each journaled inone of said cylindrical members, having its rotary axis parallel to, but spaced from the rotary axis of said cylindrical member whereby said simultaneous rotation of said cylindrical members effects. simultaneous radial displacement of said rotary tool axes with respect to the. rotary axis of. said head.

6. In cylinder shaping apparatus of the class described: a head mounted and adapted for. powered rotation; a plurality of power driven rotary tools journaled in said head and projecting therefrom whereby to. engage. the interior wall of a cylinder; and idler means including a shaft mounted in said head and projecting therefrom, a second. shaft positioned on the extended axis of said first shaft, a helical. spring coaxially positioned with respect to said shafts and connecting the same at their adjacent ends, and a roller journally mounted on the extended end. of said second shaft in position to engage said cylinder wal, whereby said second shaft and said roller mounted thereon is. adapted tobe deflected against resilient resistance from the axis of said first shaft.

'7. In cylinder shaping apparatus of the class described: a tool head; a plurality of cylindrical members journaled for limited rotation in said head about axes equally spaced from a central axis of said head, said, members having relatively immovable gear portions thereon an internal ring gear rotatably supported in said head and meshed with said gear portions whereby to effect simultaneous rotation of said members; a rotating collar for said last mentioned ring gear coaxially positioned on said ring gear and rotatable thereon; spring means positioned between said collar and ring gear to effect resilient driving connection between said members; a movably mounted locking member positioned in said. head and manually operable to clamp said rotating collar to said head to prevent rotation thereof while permitting resiliently limited rotation of said ring gear; a plurality of rotary tool shafts, each journaled in one of said members on an. axis spaced from the rotary axis of said member whereby rotation of said collar displaces said tool shafts with respect to said central axis while. maintaining the same on a circle concentric with said central axis at all times a plurality of idler shafts each concentrically journaled in one of 13 said cylindrical members; a pinion on each of said idler shafts; a pinion on each of said tool shafts; a gear on each of said idler shafts, said idler gear being meshed with the pinion on the tool shaft mounted in the same member with said last mentioned idler shaft; a coaxial bearing formed in said head; a non-rotating shank projecting within said bearing and adapted to rotatably support said head; a drive shaft coaxially journaled in said shank and projecting into said head; a first gear fixed to said drive shaft adjacent the inner end thereof and having common meshing engagement with said idler pinions whereby to simultaneously drive said idlers and tool shafts; a second drive gear fixed to said drive shaft adjacent the inner end thereof; a plurality of gears journaled in said shank and meshed with said second drive gear; a driven gear integrally formed in said head and meshed with said gears in said shank whereby to drive said head from said drive shaft; and a stationary support having a plurality of legs and a central collar portion surrounding said shank to support the same with said head adjacent the open end of a cylinder and with said tool shafts projecting thereinto, said collar portion being adapted to permit reciprocating axial motion of the shank.

DONALD W. BALDWIN.

WILFRED G. THOMPSON. WILLIAM A. 'CLEMENTS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 854,819 Georges May 28, 1907 1,217,419 Cumming Feb. 27, 1917 1,429,135 Gutenson Sept. 12, 1922 1,499,754 Sproul July 1, 1924 FOREIGN PATENTS Number Country Date 13,857 Great Britain Aug. 2, 1900 22,869 Great Britain Oct. 16, 1906 

